JP5821827B2 - Insulated electric wire for railway vehicles and cable for railway vehicles using non-halogen crosslinked resin composition - Google Patents

Description

The present invention relates to flame retardant halogen-free crosslinked resin composition is cable insulation wire and rail vehicle coated railway vehicle.

  The awareness of environmental problems is increasing worldwide, and it is required to use so-called halogen-free materials for insulated wires and cables that do not generate halogen gas during combustion. For example, an insulated wire using a halogen-free flame retardant such as a metal hydroxide is known (for example, see Patent Document 1).

  In order to obtain high flame retardance that can suppress the propagation of flames in the event of a fire, it is necessary to fill such a halogen-free flame retardant at a high level. However, there is a problem that the molding machine is restricted.

  On the other hand, insulated wires and cables used in railway vehicles and vehicles such as automobiles are required to have high oil resistance and low temperature characteristics depending on the environment in which they are used.

  In order to obtain high oil resistance, it is preferable to use a polymer having high crystallinity or a polymer having high polarity, and in order to obtain low temperature characteristics, it is preferable to use a material having a low glass transition point (Tg). It is known.

JP 2010-97881 A

  However, if a polymer with high crystallinity is used in order to obtain high oil resistance, there is a problem that flexibility is lowered and wiring property is deteriorated when applied to insulated wires and cables.

In addition, a highly polar polymer such as an ethylene vinyl acetate copolymer (EVA) having a vinyl acetate content (VA amount) of 50% by mass or more is excellent in oil resistance while maintaining flexibility at room temperature. However, there was a problem that Tg was high and the low temperature characteristics were inferior.
Further, EVA having a high VA amount has high adhesiveness at room temperature and at the time of melting, and a phenomenon in which the material wraps around and accumulates around the die during extrusion (hereinafter referred to as die scum) occurs. If the die scum adheres to the surface of an electric wire or cable, the appearance is deteriorated. In addition, EVA with a high amount of VA is sticky and has a problem of sticking of a wire or cable after molding.

The present invention has been made in view of the above-mentioned problems, has flame retardancy and excellent mechanical properties, and achieves both high oil resistance and excellent low-temperature properties, and enables sticking between dies and wires / cables. halogen-free crosslinked resin composition which can prevent an object to provide a cable for insulated wire and rail vehicles for railway vehicles covered.

In order to achieve the above object, according to the present invention, there are provided an insulated wire for railway vehicles and a cable for railway vehicles using the following non-halogen crosslinked resin composition.

[1] 0.5 to 10 parts by mass of a silicone rubber and 100 to 250 parts by mass of a metal hydroxide are contained with respect to 100 parts by mass of the base polymer. a) an ethylene-vinyl acetate copolymer (EVA) and (b) an acid-modified polyolefin resin having a glass transition point (Tg) by DSC of −55 ° C. or lower, (a): (b) = 70: 30 to 90 : together containing at 1:10 (mass ratio), that the vinyl acetate content of the base polymer (VA amount) Ru 50 to 70% by mass Roh Nharogen crosslinked resin composition is coated as an insulating layer Insulated wires for railway vehicles.

[2] The EVA is composed of two or more types of EVA having different melt mass flow rates (MFR), and includes 5 to 20% by mass of EVA having an MFR of 15 g / 10 min or more. [1] The insulated wire for a railway vehicle according to [1] .

[3] 0.5 to 10 parts by mass of silicone rubber and 100 to 250 parts by mass of metal hydroxide with respect to 100 parts by mass of the base polymer,
The base polymer contains, as main components, (a) an ethylene-vinyl acetate copolymer (EVA) and (b) an acid-modified polyolefin resin having a glass transition point (Tg) of −55 ° C. or less by DSC method, (a) : (B) = 70: 30 to 90:10 ratio (mass ratio), and the non-halogen crosslinked resin composition in which the vinyl acetate content (VA amount) of the base polymer is 50 to 70% by mass is insulated. A cable for a railway vehicle comprising an insulated electric wire for a vehicle that is coated as a layer.

[4] 0.5 to 10 parts by mass of silicone rubber and 100 to 250 parts by mass of metal hydroxide with respect to 100 parts by mass of the base polymer,
The base polymer contains, as main components, (a) an ethylene-vinyl acetate copolymer (EVA) and (b) an acid-modified polyolefin resin having a glass transition point (Tg) of −55 ° C. or less by DSC method, (a) : (B) = A non-halogen crosslinked resin composition containing 70:30 to 90:10 in a ratio (mass ratio) and having a vinyl acetate content (VA amount) of the base polymer of 50 to 70% by mass. A railway vehicle cable characterized by being coated as:

According to the present invention, a non-halogen cross-linked resin composition that has flame retardancy and excellent mechanical properties, is compatible with high oil resistance and excellent low-temperature properties, and can prevent sticking between dies, wires and cables is coated. Rail vehicle insulated wire and cable for railway vehicles has is provided.

It is sectional drawing which shows one Embodiment of the insulated wire of this invention. It is sectional drawing which shows one Embodiment of the cable of this invention.

  Hereinafter, an insulated wire and a cable according to an embodiment of the present invention will be specifically described with reference to the drawings.

(Insulated wire)
FIG. 1 is a cross-sectional view showing an embodiment of the insulated wire of the present invention.

  As shown in FIG. 1, the insulated wire 11 according to the present embodiment includes a conductor 11a made of a general-purpose material, for example, tin-plated copper, and an insulating layer 11b formed on the outer periphery of the conductor 11a.

  The insulating layer 11b is composed of a non-halogen crosslinked resin composition containing 0.5 to 10 parts by mass of silicone rubber and 100 to 250 parts by mass of metal hydroxide with respect to 100 parts by mass of the base polymer. .

The base polymer in the non-halogen crosslinked resin composition comprises, as main components, (a) an ethylene vinyl acetate copolymer (EVA) and (b) an acid-modified polyolefin having a glass transition point (Tg) by DSC of −55 ° C. or lower. The resin is contained in a ratio (mass ratio) of (a) :( b) = 70: 30 to 90:10 , and the vinyl acetate content (VA amount) of the base polymer is 50 to 70% by mass.

  In general, when there are 1, 2, 3,..., K,..., N types of polymers used for the base polymer, the VA amount in the base polymer is derived by the following formula (1). That is,

  In the above formula (1), X represents the VA amount (% by mass) of the polymer k, Y represents the ratio of the polymer k to the entire base polymer, and k represents a natural number.

  In this embodiment, if the VA amount of the base polymer of the non-halogen crosslinked resin composition used is less than 50% by mass, the oil resistance cannot be satisfied, and if it exceeds 70% by mass, the low temperature characteristics cannot be obtained. . In addition, EVA absorbs heat due to deacetic acid during combustion. Therefore, when the amount of VA is low, the flame retardancy tends to decrease.

  In the present embodiment, (a) EVA, which is one of the constituent components of the base polymer, is composed of two or more types having different melt mass flow rates (MFR), and 5% EVA having an MFR of 15 g / 10 min or more. It is preferable that -20 mass% is contained. More preferably, it is 5-15 mass%, More preferably, it is 5-10 mass%. This is because the melt flowability and productivity can be improved by setting the EVA content of the high MFR within this range. That is, if the MFR of all the EVAs used is less than 15 g / 10 min, the discharge amount at the time of extrusion molding becomes low, and the productivity may be lowered. When the EVA having an MFR of 15 g / 10 min or more is less than 5% by mass, the discharge amount at the time of extrusion molding is lowered, and the productivity may be lowered. If it exceeds 20% by mass, the resin composition may be strongly adhered, and it may be difficult to take it out from a batch kneader such as a kneader. Moreover, there is no restriction | limiting in particular about the VA amount of EVA whose MFR is 15 g / 10min or more, The whole VA amount of a base polymer should just be 50-70 mass%.

Furthermore, the content of (b) acid-modified polyolefin resin, which is another constituent component of the base polymer, is (a) in a mass ratio with respect to (a) ethylene vinyl acetate copolymer (EVA). ) = 70: 30 to greater than 90:10 (more than 30% by mass), the oil resistance is lowered. Preferably , ( a) :( b) = 80: 20 to 90:10. Further, when (b) acid-modified polyolefin having a Tg higher than -55 ° C. is used, the low temperature characteristics are lowered. The acid-modified polyolefin resin having a Tg of −55 ° C. or lower is not particularly limited, but those having low crystallinity are more flexible, and those having a melting point of 90 ° C. or lower are preferable. Specifically, ultra-low density polyethylene subjected to acid modification, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, An ethylene-octene-1 copolymer etc. can be mentioned. These polymers can also be used in combination. Moreover, since low temperature characteristics are improved by improving the adhesion with the metal hydroxide, it is effective to perform acid modification. Examples of the acid include maleic acid, maleic anhydride, fumaric acid and the like.

  In this embodiment, as long as the effect is exhibited, the base polymer may contain a polymer component other than (a) an ethylene vinyl acetate copolymer (EVA) and (b) an acid-modified polyolefin resin.

  In the present embodiment, silicone rubber, which is one of the substances added to the base polymer, causes die scum and sticks between wires and cables when the amount added is less than 0.5 parts by mass. When it exceeds the mass part, the tensile strength decreases. It is preferable to contain silicone rubber at a ratio of 0.5 to 7.5 parts by mass, and more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the base polymer.

  Examples of the silicone rubber used in this embodiment include dimethylpolysiloxane, methylvinylpolysiloxane, and methylphenylpolysiloxane. Silicone rubber is poorly compatible with EVA and moves to the surface layer portion of the material after kneading, so that it is possible to prevent sticking between the die scum and the electric cable.

  The cross-linking method used in this embodiment includes chemical cross-linking with organic peroxides or sulfur compounds, irradiation cross-linking with electron beam, radiation, etc., cross-linking using other chemical reactions, etc., but any cross-linking method is applied. Is possible.

  In the present embodiment, if the content of the metal hydroxide, which is another additive substance to the base polymer, is less than 100 parts by mass, sufficient flame retardancy cannot be obtained, If it exceeds 250 parts by mass, the low temperature characteristics cannot be ensured. The metal hydroxide is preferably contained in a proportion of 100 to 200 parts by mass, more preferably 100 to 150 parts by mass with respect to 100 parts by mass of the base polymer.

  Examples of the metal hydroxide used in the present embodiment include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and the like. The endothermic amount at the time of decomposition of calcium hydroxide is about 1000 J / g, whereas the endothermic amounts of aluminum hydroxide and magnesium hydroxide are as high as 1500 to 1600 J / g, which is preferable because of good flame retardancy. . The flame retardant can be surface-treated with a silane coupling agent, a titanate coupling agent, a fatty acid such as stearic acid, and the like in consideration of dispersibility and the like.

  Non-halogen cross-linked resin compositions composed of these materials include cross-linking aids, flame retardant aids, UV absorbers, light stabilizers, softeners, lubricants, colorants, reinforcing agents, and surface active agents as necessary. An agent, an inorganic filler, a plasticizer, a metal chelating agent, a foaming agent, a compatibilizer, a processing aid, a stabilizer and the like can be added.

  In this embodiment mode, the insulating layer may be a single layer or may have a multilayer structure. Specific examples of a multilayer structure include a structure obtained by extrusion coating the non-halogen crosslinked resin composition on the outermost layer and a polyolefin resin on the outermost layer. Examples of the polyolefin resin include low density polyethylene, EVA, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer, and maleic anhydride polyolefin. Or 2 or more types can be mixed and used. Furthermore, you may give a separator, a braiding, etc. as needed.

  As the material used for the insulating layer other than the outermost layer, a rubber material is also applicable, such as ethylene-propylene copolymer rubber (EPR), ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene rubber ( NBR), hydrogenated NBR (HNBR), acrylic rubber, ethylene-acrylate copolymer rubber, ethylene octene copolymer rubber (EOR), ethylene-vinyl acetate copolymer rubber, ethylene-butene-1 copolymer Rubber (EBR), butadiene styrene copolymer rubber (SBR), isobutylene-isoprene copolymer rubber (IIR), block copolymer rubber having a polystyrene block, urethane rubber, phosphazene rubber and the like. It can use individually or in mixture of 2 or more types.

  Moreover, it is not limited to the said polyolefin resin and rubber material, If there is insulation, there will be no restriction | limiting in particular. If necessary, flame retardant, flame retardant aid, crosslinking agent, crosslinking aid, UV absorber, light stabilizer, softener, lubricant, colorant, reinforcing agent, surfactant, antioxidant, inorganic filler , Coupling agents, plasticizers, metal chelating agents, foaming agents, compatibilizers, processing aids, stabilizers, and the like can be added. The crosslinking treatment includes chemical crosslinking with an organic peroxide or a sulfur compound, irradiation crosslinking with an electron beam, radiation, and the like, and crosslinking using other chemical reactions, and any crosslinking method can be applied.

(cable)
FIG. 2 is a cross-sectional view showing an embodiment of the cable of the present invention.

  As shown in FIG. 2, the cable 12 according to the present embodiment includes a conductor 12a made of a general-purpose material such as tin-plated copper, an insulating layer 12b formed on the outer periphery of the conductor 12a, and an insulating layer 12b. And a sheath 12c formed on the outer periphery.

  The insulating layer 12b is made of, for example, one or more polymers selected from the group consisting of ethylene-butene-1 copolymer rubber, polybutylene naphthalate, polybutylene terephthalate, polyphenylene oxide, and polyether ether ketone. You may form from the above-mentioned non-halogen crosslinked resin composition.

The sheath 12c is formed from the above-mentioned non-halogen crosslinked resin composition.
In addition, since it is the same as that of the case of the above-mentioned insulated wire about the detail of a non-halogen crosslinked resin composition, description is abbreviate | omitted.

  In the present embodiment, the sheath may be formed of a single layer or a multilayer structure. Specific examples of a multilayer structure include a structure obtained by extrusion coating the non-halogen crosslinked resin composition on the outermost layer and a polyolefin resin on the outermost layer. Examples of the polyolefin resin include low density polyethylene, EVA, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-glycidyl methacrylate copolymer, and maleic anhydride polyolefin. Or 2 or more types can be mixed and used. Furthermore, you may give a separator, a braiding, etc. as needed.

(Non-halogen crosslinked resin composition)
The non-halogen crosslinked resin composition used in the embodiment of the present invention contains 0.5 to 10 parts by mass of silicone rubber and 100 to 250 parts by mass of metal hydroxide with respect to 100 parts by mass of the base polymer. The base polymer contains, as main components, (a) an ethylene vinyl acetate copolymer (EVA) and (b) an acid-modified polyolefin resin having a glass transition point (Tg) by DSC of −55 ° C. or less ( a): (b) = 70: 30 to 100: 0 in a proportion (mass ratio), and the vinyl acetate content (VA amount) of the base polymer is 50 to 70 mass%. Details of the non-halogen crosslinked resin composition are as described above.

The non-halogen crosslinked resin composition used in the embodiment of the present invention can be used for various applications, but has both flame resistance and excellent mechanical properties, as well as high oil resistance and excellent low-temperature properties, and can be used for die dies and electric wires. -Since it can prevent sticking of cables, it can be used suitably for the insulation layer of an insulated wire and the sheath of a cable. In particular, it can be suitably used for a vehicle insulated wire and a vehicle cable.

  Below, the cable of this invention is demonstrated more concretely using an Example. Note that the present invention is not limited in any way by the following examples.

( Reference Example 1)
The cable shown in FIG. 2 was manufactured as follows. That is, 80 conductors / 0.40 mm tin-plated copper conductor is used as the conductor, and 100 parts by mass of ethylene-butene-1 copolymer rubber (manufactured by Mitsui Chemicals, trade name: Toughma A-4050S) as the insulating layer. In contrast, a resin composition to which 2 parts by mass of an organic peroxide (manufactured by NOF Corporation, trade name: Perbutyl P) (Perbutyl is a registered trademark) was used, and the sheath was composed of the compounding materials shown in Table 1. A non-halogen crosslinked resin composition was used. These resin compositions are extruded on the outer periphery of the conductor by a two-layer extrusion using a 4.5 inch continuous steam cross-linking extruder so that the insulating layer has a thickness of 0.45 mm and the sheath has a thickness of 1.67 mm. And coated to an outer diameter of 8.60 mm. Crosslinking was performed for 3 minutes using 1.8 MPa high-pressure steam to obtain a cable. In addition, 1-3 EVA in Table 1 is EVA less than MFR15g / 10min.

  In this case, as the material of the non-halogen crosslinked resin composition constituting the sheath, EVA (VA: 60% by mass) (manufactured by LANXESS, trade name: Revaprene 600) (Revaprene is a registered trademark), 100 parts by mass, silicone rubber ( 5 parts by weight of dimethylpolysiloxane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KE76), 2 parts by weight of organic peroxide (manufactured by NOF Corporation, trade name: Perbutyl P) (Perbutyl is a registered trademark), magnesium hydroxide ( 100 parts by mass of Kyowa Chemical Co., Ltd., trade name: Kisuma 5L) (Kisuma is a registered trademark) were used.

  In addition, the insulated wire which concerns on embodiment of this invention shown in FIG. 1 uses the insulating layer which consists of a non-halogen crosslinked resin composition which consists of a compounding material shown in Table 1 instead of the sheath in the cable shown in FIG. Were similarly produced. As a result of the evaluation, the effect of the present invention was achieved.

  The obtained cable was evaluated by the following various evaluation tests required especially for railway vehicle applications. The evaluation results are shown in Table 1.

[Evaluation test]
(Evaluation of kneading processability)
The material for blending the sheath shown in Table 1 was kneaded with a 25 L kneader at a set temperature of 50 ° C., and after raising the temperature to 150 ° C. by self-heating, the chamber was tilted and the material dropped naturally by hand. Those that could be dropped were marked with ◯, and those that could not be scraped out were marked with x.

(Evaluation of extrusion productivity)
When the insulation layer and sheath are coated on the cable, if the maximum take-up speed is 20 m / min or more when two-layer extrusion is performed with a 4.5 inch continuous steam crosslinking extruder, ◎, 1 m / min or more and 20 m / min If it was less than ◯, the case where it could not be picked up was marked as x.

(Evaluation of die scum)
When covering the cable with the insulating layer and the sheath, the die after 100 m extrusion when the two-layer extrusion was carried out with a 4.5 inch continuous steam crosslinking extruder was visually observed to confirm the presence or absence of the die scum. If there was a die scum, it was rated as x.

(Evaluation with sticking)
When covering a cable with an insulating layer and a sheath, when a two-layer extrusion is carried out with a 4.5 inch continuous steam cross-linking extruder, the cable is wound around a bobbin having a diameter of 450 mm and unwound after 60 minutes. If the two stick together, it was marked as ×, and if it was clean without sticking, it was marked as ◎.

(Evaluation of flame retardancy)
A vertical flame retardant test in accordance with EN60332-1-2 was performed. 550mm cable is supported vertically, flame is applied at 475mm from the top for 60 seconds, removed, and after flame extinguishes in the range of 50mm to 540mm from the top, ◎, after flame exceeds the above range The case was marked with x.

(Evaluation of sheath)
The sheath was evaluated by cutting the insulating layer, punching the sheath portion into a No. 6 dumbbell test piece, and carrying out the following tests.

Tensile strength evaluation:
In accordance with EN60881-1-1, a tensile test was performed at a tensile speed of 200 mm / min. Those having a tensile strength of 10 MPa or more were rated as ◎, and those having a tensile strength lower than 10 MPa were rated as x.

Oil resistance evaluation:
In accordance with EN60881-2-1, a tensile test was conducted after 168 hours immersion in test oil IRM903 heated to 70 ° C. Those with an elongation change rate of 40% or less were marked with ◎, and those with a rate of elongation exceeding 40% were marked with ×.

Low temperature characteristic evaluation:
In accordance with EN60881-1-4, ◎ indicates an elongation of 30% or more at -40 ° C, and x indicates an elongation of less than 30%.

(Comprehensive evaluation)
As a comprehensive evaluation, all evaluations with ◎ are excellent (◎), evaluations with ◎ and ○ are good (○), and if any evaluation fails (×), it will be rejected ( X).

(Examples 1 to 13 )
In Reference Example 1, cables of Examples 1 to 13 were produced in the same manner as Reference Example 1 except that the material for blending the sheath was changed to that shown in Examples 1 to 13 in Table 1.

The obtained cable was evaluated by various evaluation tests as in Reference Example 1. The evaluation results are shown in Table 1.

As shown in Table 1, in the case of Reference Example 1 and Examples 1 to 3 , the extrusion processability was “good” and the overall evaluation was “good”.

The kneadability of Examples 8 and 10 and the extrudability of Examples 11 and 13 were ○, and the overall evaluation of Examples 8 , 10 , 11 and 13 was ○.

In the case of Examples 4 to 7 , 9 and 12 , all evaluations were ◎, and the overall evaluation was ◎.

(Comparative Examples 1-8)
In Reference Example 1, cables of Comparative Examples 1 to 8 were produced in the same manner as Reference Example 1 except that the sheath compounding material was changed to that shown in Table 2.

The obtained cable was evaluated by various evaluation tests as in Reference Example 1. The evaluation results are shown in Table 2.

  As shown in Table 2, in the case of Comparative Example 1, the VA content of the base polymer was low, and the flame retardancy and oil resistance were x. Therefore, the overall evaluation was x.

  In the case of Comparative Example 2, the VA content of the base polymer was high, and the low temperature characteristics were x. Therefore, the overall evaluation was x.

  In the case of Comparative Example 3, the amount of acid-modified polyolefin added was too large, and the oil resistance was x. Therefore, the overall evaluation was x.

  In the case of Comparative Example 4, the Tg of the acid-modified polyolefin was high and the low temperature characteristics were x. Therefore, the overall evaluation was x.

  In the case of Comparative Example 5, the amount of magnesium hydroxide added was low, and the flame retardancy was x. Therefore, the overall evaluation was x.

  In the case of Comparative Example 6, the amount of magnesium hydroxide added was large and the low temperature characteristics were x. Therefore, the overall evaluation was x.

  In the case of Comparative Example 7, since silicone rubber was not added, die scum was generated and the cable was sticky. Therefore, the overall evaluation was x.

  In the case of Comparative Example 8, the tensile strength decreased because the amount of silicone rubber added was large. Therefore, the overall evaluation was x.

11: insulated wire, 11a: conductor, 11b: insulating layer 12: cable, 12a: conductor, 12b: insulating layer, 12c: sheath

Claims (4)

Containing 100 to 250 parts by mass of silicone rubber and 100 to 250 parts by mass of metal hydroxide with respect to 100 parts by mass of the base polymer;
The base polymer contains, as main components, (a) an ethylene-vinyl acetate copolymer (EVA) and (b) an acid-modified polyolefin resin having a glass transition point (Tg) of −55 ° C. or less by DSC method, (a) : (b) = 70: 30~ 90: 10 with a proportion (mass ratio) of the vinyl acetate content of the base polymer (VA amount) Ru 50 to 70% by mass Roh Nharogen crosslinked resin composition An insulated wire for railway vehicles, characterized in that is coated as an insulating layer. The EVA is composed of two or more types of EVA having different melt mass flow rates (MFR), and contains 5 to 20% by mass of EVA having an MFR of 15 g / 10 min or more. The insulated wire for rail vehicles described . Containing 100 to 250 parts by mass of silicone rubber and 100 to 250 parts by mass of metal hydroxide with respect to 100 parts by mass of the base polymer;
The base polymer contains, as main components, (a) an ethylene-vinyl acetate copolymer (EVA) and (b) an acid-modified polyolefin resin having a glass transition point (Tg) of −55 ° C. or less by DSC method, (a) : (B) = 70: 30 to 90:10 ratio (mass ratio), and the non-halogen crosslinked resin composition in which the vinyl acetate content (VA amount) of the base polymer is 50 to 70% by mass is insulated. A cable for a railway vehicle comprising an insulated electric wire for a vehicle that is coated as a layer. Containing 100 to 250 parts by mass of silicone rubber and 100 to 250 parts by mass of metal hydroxide with respect to 100 parts by mass of the base polymer;
The base polymer contains, as main components, (a) an ethylene-vinyl acetate copolymer (EVA) and (b) an acid-modified polyolefin resin having a glass transition point (Tg) of −55 ° C. or less by DSC method, (a) : (B) = A non-halogen crosslinked resin composition containing 70:30 to 90:10 in a ratio (mass ratio) and having a vinyl acetate content (VA amount) of the base polymer of 50 to 70% by mass. A railway vehicle cable characterized by being coated as: